Classics - John Snow: The London Cholera Epidemic of 1854 It wasn't until 1854 that Cholera struck England once again, that Snow was able to legitimate his argument that Cholera was spread through contaminated food or water. Snow, in investigating the epidemic, began plotting the location of deaths related to Cholera (see illustration). At the time, London was supplied its water by two water companies. One of these companies pulled its water out of the Thames River upstream of the main city while the second pulled its water from the river downstream from the city. A higher concentration of Cholera was found in the region of town supplied by the water company that drew its water form the downstream location.
List of terrestrial ecoregions (WWF) This is a list of terrestrial ecoregions as compiled by the World Wildlife Fund (WWF). The WWF identifies terrestrial, freshwater, and marine ecoregions. The terrestrial scheme divides the Earth's land surface into 8 terrestrial ecozones, containing 867 smaller ecoregions. Each ecoregion is classified into one of 14 major habitat types, or biomes. Additional ecoregions for Antarctic Realm are currently being incorporated (based on Terauds et al. 2012). Antarctic Realm - Tundra Biome: 1 North-east Antarctic Peninsula; 2 South Orkney Islands; 3 North-west Antarctic Peninsula; 4 Central south Antarctic Peninsula; 5 Enderby Land; 6 Dronning Maud Land; 7 East Antarctica; 8 North Victoria Land; 9 South Victoria Land; 10 Transantarctic Mountains; 11 Ellsworth Mountains; 12 Marie Byrd Land; 13 Adelie Land; 14 Ellsworth Land; 15 South Antarctic Peninsula.
The Nature of Geographic Information course home page Navigation Start Here Orientation Resources Course Text What Is Color Blindness? - Eye M.D.-approved information from EyeSmart In the retina (the light-sensitive tissue lining the back of the eye), there are two types of cells that detect light: rods and cones. Rods detect only light and dark and are very sensitive to low light levels. Cone cells detect color and are concentrated near the center of your vision. Big ideas from small places Editor's Note: Parag Khanna is a senior research fellow at the New America Foundation, visiting senior fellow at the European Council on Foreign Relations, and author of The Second World and How to Run the World. David Skilling is founding director at Landfall Strategy Group, a Singapore-based advisory firm. By Parag Khanna and David Skilling – Special to CNN
National Atlas home page The National Map is now offering a collection of small-scale datasets that can be downloaded for free. Although the 1997-2014 Edition of the National Atlas of the United States was retired in September 2014, The National Map recognizes the importance of continuing to make a collection of the small-scale datasets, originally developed for the National Atlas, available to users. Small-scale maps have an advantage over large-scale maps when there is a need to show a large area in a single view. This makes small-scale maps an ideal solution for scientists, decision-makers, and planners needing to provide a geographical context for the research projects. Generally, certain geographical and feature details found in large-scale maps are limited or omitted in small-scale maps.
Color Blindness Article By Dr Alex Wade, Research Fellow at Stanford University (this article appeared in Planet Medica, April 2000) The next time you go strawberry picking, imagine how much harder it would be if the fruit were the same colour as the leaves. If you are a man, there is a 10% chance that they are! So is this a problem you need to worry about?
International Programs - Information Gateway Frequently Asked Questions (FAQ) 1. What is the International Data Base? The International Data Base (IDB) offers a variety of demographic indicators for countries and areas of the world with a population of 5,000 or more. World and Region demographic indicators in the IDB, including population totals, exclude the populations of countries and areas with fewer than 5,000 people. The IDB has provided access to demographic data for over 25 years to governments, academics, other organizations, and the public.